Improvement in reflectors



A. WILHELM. Beieciurs;

Patented April 7, 1874.

ANo.149

UNITED STATES PATENT OFFICE I |MPR1ovEMENT IN REFLEcToRs..

Specification forming part of Letters Patent No. 119,555,

dated April 7, 1874 application filed December 2, 1873.l

to the accompanying drawings vmaking part of this specification, inwhich- Flgures l and 2 are vertical sections through the center of therelector.

Similarlts' of reference indicatel corresponding parts in the twofigures.

The object of the invention is to improve that class of light-reflectorswhich are suspended horizontally from the ceilings of churches, halls,depots, places of amusement, Sto., and are designed to reflect anddiffuse the rays of light coming from aseries of burners downward andoutward, so as to perfectly illuminate these places.

The form of reflector generally employed is that of a frustum of a coneinserted into the ceiling, or a cone suspended in the center of thefrustum.` These reectors are the so-styled double-cone reflectors. Theyhave two serious defects, which, by my improvement, I design to remedy,besides producing a more perfect and stronger reflector than heretoforemade.

The `first defect of the so-called double-cone reiiectoris, that thefrustum and inner cone are two distinct parts, their reiieeting surfacesbeing separated, leaving an open space around the upper part of thereflector. The reflector may be suspended from the inner cone, or fromthe circumference of the frustum; but in either case it necessitates theconnection of the frustum with the inner cone by strong braces of wireor strips of metal. The opening caused by the separation of the tworeiiecting-'surfaces around the top of the reiiector causes a greaterloss of light than is absolutely necessary. f

The second defect of the so-called doublecone reflector is, that theform of the reflector does not give the constructer sufficient controlover the rays of light to illuminate a given space evenly, or obtain thebest results with a given number of burners, as he would have if thereliecting-surfaces were so curved as to positively reflect the lightwhere it is needed, and thus overcome the before-named second defect ofthe old-style refiector, thereby producing a correctly-formed andstrongly-constructed light-reiiector.

Referring to the drawings, A represents the inner pendant; A A, thecentral basin, and A" Al the outer1 rim. The dotted lines show themanner of constructing the reiiectingsurfaces, and the resultantdirection of the reiiected rays of light coming from lights placed onthe focus-.line F F.

In Fig. l I construct the reflector of the inner pendant A', the centralbasin A A, and the outer rim A A. The inner pendant A is formed of theconvex curves cv b c' b. At b b begins the central basin A A, which isformed of the concave elliptic curves b a b b a b, and at bb begins theouter rim A A, which is formed of the convex curves b c b c, and ispendent toward and below the ring of lightsv placed on the focus-line FF of the basin part A A. All the curves forming the different parts ofthe body of the reflector are continuous of each other. The convexcurves are segments of circles, and the concave curves are segments ofellipses. FF is the focus-line of the basin partA A ofthe reiiector. Therays of light (represented in the drawing by the dotted lines) fallingon the convex curves c b c b c b c b are divergingly reiiected downward7and those rays falling on the concave elliptic curves b a b b c b arereflected convergingly to the other focuses of the ellipses, and,passing through those focuses, diverge downwardly.

It will be seen by the direction of the dotted lines, representing thereflected rays of light coming from lights placed on the focusline F Fof the basin part A A, that all the light is reliected downwardly withinthe angles c F c c F c; consequently all the light is utilized andreflected in the space which is to be illuminated.

It will also be seen that by making the inner pendant A', the centralbasin A A, and the outer rim A A continuous of each other, astrongstructure is produced, and the reflector can, therefore, besuspended either from the inner pendant without extra support on `thecircumference, or from the outer rim or circumference Without eXtrasupport for the inner pendant. p

Various modifica-tions may be made. In Fig. 2 the inner pendant orprojection A', the central basin A A, and the outer rim A A pendentbelow the focus-line F F of the basin part A A, are formed of theconcave elliptic curves c a c c a c. of a single curve, the distinctivefeatures of the different parts is not so deiined, as shown in Fig. 1.Yet the principle oi' a continuous rciectingourved surface, formingparts A', A

` A,'and A A, is also plainly demonstrated in Fig. 2.

It will also be seen that by the dotted hues, representing rays fallingon the refl ectin g-surfaces c a c c al o of the reflector, they areconverging to the other focuses of the ellipses of which the curves aresegments, and, passing through the focuses, diverge downwardly. Thus thelight is utilized in the same manner as shown in Fig. l, and the generalstructure of the retlector is equally as strong, and the same inprinciple.

The contour of the reflector may be circular, oblong, oval, orpolygonal.

I am aware that reflectors have been con- As these parts are formed`structed of an outer and inner part, as shown in the'doublecone reector,or in the reflector constructed for a light-house; but in both of thesereflectors the inner and outer parts are separated and not continuous.In the lighthous'ereector the reilecting-surfaces of the outer and innerparts are formed of the parabolic curve, and all the rays reected fromit are reflected in parallel lines downward; but by the construction ofmy reflectingsurfaces the light will be diffused downward and outward.

. Having shown and described the particular advantages of my improvedform and con-y struction for a reflector, what I claim as my invention,and desire to secure by Letters Patent, is

A ceiling-reliector having a continuous curved reecting-surface, thesame consisting of an inner pendant or projection, a central basin ofelliptical form in vertical section, and an outer rim pendent toward orbelow the lights, in combination with the ring of lights placed on thefocus-line of the basin portion of the reector, for the purpose hereinset forth.

Witnesses: AUGUST WILHELM.

JOHN A. WIEDERSHEIM, G. S. HETHERINGTON.

